Some affluent Northerners would regularly travel to Hot Springs, Arkansas — a tree-lined, lush landscape filled with natural hot springs. There, they would find the exercise machines of Gustav Zander (pictured above). And so began America's love-hate relationship with working out at the gym.

"If you imagine the 1910s or 1920s, people's jobs and lives were governed by machines in ways they just had never been before," said Carolyn de la Pena, PhD, an American studies professor at the University of California, Davis, and author of The Body Electric: How Strange Machines Built the Modern American. "It makes sense that people started to mimic machines in their everyday...lives."

The "strange and scary-looking machines" of Gustav Zander were originally developed in Sweden to systematically strengthen all parts of the body, de la Pena said. American resorts in Hot Springs imported them to the United States, where they became part of the destination's culture of relaxation and wellbeing. (Some Zander machines are still visible in Hot Springs today.)

The Zander machines were developed at the same time as some other mechanical exercise systems, which were primarily found in universities, as colleges began to worry that too much academic work, and not enough physical activity, would harm the strength and productivity of the students. As college-aged students began to focus on physical strength at school, the trends spread, developing into the gyms we know today.

"These machines were really the first time that you could show that you were the one who was the most fit, or that you were the strongest, because fitness data became quantifiable," de la Pena said. "These machines ultimately shaped our modern gyms. Today, when students go to college, it's impossible to imagine that there wouldn't be a nice gym."

Still, the original pieces of gym equipment worked a little different from the ones we use today. "Machines are active now — you have to lift the weight or do the action to make them work," de la Pena said. "But the Zander machines were attached to a wheel, belt and electric generator, which would be driving their power and moving the machine. It was thought that giving people a repeated stimulus would build muscle."

Above, check out original photos of the Gustav Zander exercise machines.